Microelectronic packages called "multi chip modules" or "hybrids" are assembled using unpackaged semiconductor dice. Prior to the assembly procedure, each unpackaged die must be tested to measure its quality and reliability. This has led to the development of test procedures suitable for testing unpackaged semiconductor dice. Known-good-die (KGD) refers to an unpackaged die having the same quality and reliability as the equivalent packaged die.
Testing includes burn-in testing wherein the dice are heated while the integrated circuits are electrically biased. In addition, the dice are subject to speed and functionality tests to check the performance of the integrated circuits and devices formed on the dice. Among the parameters tested are input and output voltages, capacitance and current specifications. Memory chips are also put through logic tests wherein data storage, retrieval capabilities and response times are measured.
For testing and burning-in unpackaged dice, temporary carriers have been used in the manufacturing process in place of conventional single chip packages. This type of carrier typically includes a base for retaining and housing a single die. The carrier also includes an interconnect that allows a temporary electrical connection to be made between an individual die and external test circuitry. Carriers for testing unpackaged dice are disclosed in U.S. Pat. No. 4,899,107 to Corbett et al. and U.S. Pat. No. 5,302,891 to Wood et al., which are commonly assigned with the present application.
This type of carrier allows tests to be performed on an unpackaged die without damaging the die. The bond pads of a die are particularly susceptible to damage during the testing procedures. Although these types of carriers are suitable for testing a singulated unpackaged die, it would be advantageous to be able to test multiple dice at the same time. This would simplify the handling and test procedures and allow testing to proceed without a separate carrier for each die. In addition, it would be advantageous to perform both burn-in, speed and functionality testing using a common test fixture.
In view of the foregoing, it is an object of the present invention to provide an improved method and apparatus for test and burn-in of unpackaged dice.
It is a further object of the present invention to provide an improved method and apparatus for testing unpackaged dice that permits multiple dice to be tested at the same time.
It is a further object of the invention to provide an improved method and apparatus for testing unpackaged dice that are simple, inexpensive and compatible with volume manufacturing processes and equipment.
It is yet another object of the present invention to provide a method and apparatus for performing speed and functionality testing as well as burn-in testing of multiple dice with a single test fixture.
Other objects, advantages, and capabilities of the present invention will become more apparent as the description proceeds.